The present invention relates to anti-skid brake control systems, and more particularly to an anti-skid brake control system incorporated with dual hydraulic braking circuits for independently controlling respective braking fluids supplied to the right and left rear-wheel brake cylinders at a rate of pressure increase lower than the rate of pressure increase in a tandem master cylinder.
In automobiles, dual hydraulic braking circuits are respectively connected to the right and left rear-wheel brake cylinders to ensure the safety of the automobile, and an electronic anti-skid brake control apparatus is incorporated with each of the braking circuits to avoid skidding of the automobile in sudden braking operation. Such an electronic anti-skid brake control apparatus as disclosed in U.S. Pat. Nos. 3,809,437, 3,830,550, and 4,095,851, comprises a cut-off valve and a hydraulic capacity controller disposed within a hydraulic braking circuit connecting a master cylinder to wheel brake cylinders, wherein in an anti-skid operation, the cut-off valve first blocks passage of pressurized fluid from the master cylinder to the wheel brake cylinders, and then the capacity controller is conditioned for its pressure decreasing operation for effecting the anti-skid operation. The electronic anti-skid brake control apparatus further includes an expensive servomotor for pneumatically actuating the cut-off valve and the capacity controller in response to electric signals from a skid-sensor. In application of the electronic anti-skid brake control apparatus, it is required to incorporate such an expensive servomotor with each of the hydraulic braking circuits, resulting in the increase of the production cost of the control system.